From 353d60d3ebc353aef474633e7064067a2ef343ce Mon Sep 17 00:00:00 2001
From: sanine <sanine.not@pm.me>
Date: Wed, 22 Feb 2023 01:02:45 -0600
Subject: implement and demo basic obj loading

---
 src/import/import.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 186 insertions(+), 7 deletions(-)

(limited to 'src')

diff --git a/src/import/import.c b/src/import/import.c
index f860396..e2fc250 100644
--- a/src/import/import.c
+++ b/src/import/import.c
@@ -1,21 +1,200 @@
 #include <lua.h>
-#include <honeysuckle.h>
+#include <lauxlib.h>
+#include "util/util.h"
 #include "import.h"
 
 #define TINYOBJ_LOADER_C_IMPLEMENTATION
 #include <tinyobj/tinyobj_loader_c.h>
 
-int dummy(lua_State *L)
+
+void read_file(void *ctx, const char *filename, int is_mtl, const char *obj_filename, char **buf, size_t *len)
 {
-	return 0;
+	FILE *f = fopen(filename, "rb");
+	fseek(f, 0, SEEK_END);
+	*len = ftell(f);
+	fseek(f, 0, SEEK_SET);
+
+	*buf = malloc(*len);
+	fread(*buf, *len, 1, f);
+	fclose(f);
 }
 
 
-void setup_import(lua_State *L, int honey_tbl)
+static void push_float_array(lua_State *L, float *arr, size_t len)
+{
+	lua_createtable(L, len, 0);
+	int tbl = lua_gettop(L);
+	for (int i=0; i<len; i++) {
+		lua_pushnumber(L, arr[i]);
+		lua_rawseti(L, tbl, i+1);
+	}
+}
+
+
+static void push_int_array(lua_State *L, int *arr, size_t len)
 {
-	hs_create_table(L,
-		hs_str_cfunc("dummy", dummy),
+	lua_createtable(L, len, 0);
+	int tbl = lua_gettop(L);
+	for (int i=0; i<len; i++) {
+		lua_pushinteger(L, arr[i]);
+		lua_rawseti(L, tbl, i+1);
+	}
+}
+
+
+static void push_material(lua_State *L, tinyobj_material_t mtl)
+{
+	lua_createtable(L, 0, 18);
+	int tbl = lua_gettop(L);
+
+	lua_pushstring(L, mtl.name);
+	lua_setfield(L, tbl, "name");
+
+	push_float_array(L, mtl.ambient, 3);
+	lua_setfield(L, tbl, "ambient");
+	push_float_array(L, mtl.diffuse, 3);
+	lua_setfield(L, tbl, "diffuse");
+	push_float_array(L, mtl.specular, 3);
+	lua_setfield(L, tbl, "specular");
+	push_float_array(L, mtl.transmittance, 3);
+	lua_setfield(L, tbl, "transmittance");
+	push_float_array(L, mtl.emission, 3);
+	lua_setfield(L, tbl, "emission");
+	lua_pushnumber(L, mtl.shininess);
+	lua_setfield(L, tbl, "shininess");
+	lua_pushnumber(L, mtl.ior);
+	lua_setfield(L, tbl, "ior");
+	lua_pushnumber(L, mtl.dissolve);
+	lua_setfield(L, tbl, "dissolve");
+
+	lua_pushinteger(L, mtl.illum);
+	lua_setfield(L, tbl, "illum");
+
+	lua_pushinteger(L, mtl.pad0);
+	lua_setfield(L, tbl, "pad0");
+
+	lua_pushstring(L, mtl.ambient_texname);
+	lua_setfield(L, tbl, "ambient_texname");
+	lua_pushstring(L, mtl.diffuse_texname);
+	lua_setfield(L, tbl, "diffuse_texname");
+	lua_pushstring(L, mtl.specular_texname);
+	lua_setfield(L, tbl, "specular_texname");
+	lua_pushstring(L, mtl.specular_highlight_texname);
+	lua_setfield(L, tbl, "specular_highlight_texname");
+	lua_pushstring(L, mtl.bump_texname);
+	lua_setfield(L, tbl, "bump_texname");
+	lua_pushstring(L, mtl.displacement_texname);
+	lua_setfield(L, tbl, "displacement_texname");
+	lua_pushstring(L, mtl.alpha_texname);
+	lua_setfield(L, tbl, "alpha_texname");
+}
+
+
+int tinyobj_parse_obj_bind(lua_State *L)
+{
+	tinyobj_attrib_t attrib;
+	tinyobj_shape_t *shapes;
+	size_t num_shapes;
+	tinyobj_material_t *materials;
+	size_t num_materials;
+
+	const char *file_name = luaL_checkstring(L, 1);
+	unsigned int flags = luaL_checkinteger(L, 2);
+
+	int result = tinyobj_parse_obj(
+		&attrib, &shapes, &num_shapes, &materials, &num_materials, 
+		file_name, read_file, L, flags
 	);
 
-	lua_setfield(L, honey_tbl, "import");
+	if (result != TINYOBJ_SUCCESS) {
+		luaL_error(L, "failed to parse OBJ file \"%s\"", file_name);
+	}
+
+	/* push attrib */
+	lua_createtable(L, 0, 7);
+	int attrib_tbl = lua_gettop(L);
+
+	/* push attrib.pad0 */
+	lua_pushinteger(L, attrib.pad0);
+	lua_setfield(L, attrib_tbl, "pad0");
+
+	/* attrib.vertices */
+	push_float_array(L, attrib.vertices, 3*attrib.num_vertices);
+	lua_setfield(L, attrib_tbl, "vertices");
+
+	/* attrib.normals */
+	push_float_array(L, attrib.normals, 3*attrib.num_normals);
+	lua_setfield(L, attrib_tbl, "normals");
+
+	/* attrib.texcoords */
+	push_float_array(L, attrib.texcoords, 3*attrib.num_texcoords);
+	lua_setfield(L, attrib_tbl, "texcoords");
+
+	/* attrib.faces */
+	lua_createtable(L, attrib.num_faces, 0);
+	int face_array_tbl = lua_gettop(L);
+	for (int i=0; i<attrib.num_faces; i++) {
+		lua_createtable(L, 0, 3);
+		int face_tbl = lua_gettop(L);
+		/* push struct elements */
+		lua_pushinteger(L, attrib.faces[i].v_idx);
+		lua_setfield(L, face_tbl, "v_idx");
+		lua_pushinteger(L, attrib.faces[i].vt_idx);
+		lua_setfield(L, face_tbl, "vt_idx");
+		lua_pushinteger(L, attrib.faces[i].vn_idx);
+		lua_setfield(L, face_tbl, "vn_idx");
+		/* append table into array */
+		lua_rawseti(L, face_array_tbl, i+1);
+	}
+	lua_setfield(L, attrib_tbl, "faces");
+
+	/* attrib.face_num_verts */
+	push_int_array(L, attrib.face_num_verts, attrib.num_face_num_verts);
+	lua_setfield(L, attrib_tbl, "face_num_verts");
+
+	/* attrib.material_ids 
+	 * (we use the same len as face_num_verts because materials are per face) 
+	 */
+	push_int_array(L, attrib.material_ids, attrib.num_face_num_verts);
+	lua_setfield(L, attrib_tbl, "material_ids");
+
+	/* shapes */
+	lua_createtable(L, num_shapes, 0);
+	int shape_array_tbl = lua_gettop(L);
+	for (int i=0; i<num_shapes; i++) {
+		lua_createtable(L, 0, 3);
+		int shape_tbl = lua_gettop(L);
+		/* struct elements */
+		lua_pushstring(L, shapes[i].name);
+		lua_setfield(L, shape_tbl, "name");
+		lua_pushinteger(L, shapes[i].face_offset);
+		lua_setfield(L, shape_tbl, "face_offset");
+		lua_pushinteger(L, shapes[i].length);
+		lua_setfield(L, shape_tbl, "length");
+		/* append to array */
+		lua_rawseti(L, shape_array_tbl, i+1);
+	}
+	
+	/* materials */
+	lua_createtable(L, num_materials, 0);
+	int materials_array_tbl = lua_gettop(L);
+	for (int i=0; i<num_materials; i++) {
+		push_material(L, materials[i]);
+		lua_rawseti(L, materials_array_tbl, i+1);
+	}
+	
+	return 3;
+}
+
+
+
+void setup_import(lua_State *L, int honey_tbl)
+{
+	struct honey_tbl_t tinyobj[] = {
+		H_FUNC("parse_obj", tinyobj_parse_obj_bind),
+		H_INT("FLAG_TRIANGULATE", TINYOBJ_FLAG_TRIANGULATE),
+		H_END,
+	};
+	create_table(L, tinyobj);
+	lua_setfield(L, honey_tbl, "tinyobj");
 }
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